Pfizer hopes to submit COVID-19 vaccine data for youngest kids in weeks

Signage outside Pfizer headquarters in New York, U.S., on Sunday, Nov. 7, 2021. Pfizer Inc. is aiming to submit data from its experimental Covid-19 pill to U.S. regulators by the Nov. 25 Thanksgiving holiday, potentially clearing the way for an emerg

Pfizer now hopes to tell U.S. regulators how well its COVID-19 vaccine works in the littlest kids by late May or early June.

Pfizer is testing three extra-small doses of its vaccine in children under 5 after two shots didn't prove quite strong enough. Initial results had been expected last month but the company laid out the latest timeline Tuesday during its discussion of quarterly financial results.

Currently in the U.S., only children ages 5 or older can be vaccinated, using Pfizer’s vaccine -- leaving 18 million younger tots unprotected.

RELATED: 3 out of 4 US kids have had COVID-19, CDC researchers estimate

Rival Moderna hopes to be the first to offer vaccinations for the youngest children. Last week, it filed with the Food and Drug Administration data it hopes will prove two of its low-dose shots work in children younger than 5. Moderna also has filed FDA applications for older kids, although the agency hasn’t ruled on them.

The FDA already has set tentative dates in June to publicly review data on COVID-19 vaccines for tots under 5, from either or both companies.

Three out of every four U.S. children have been infected with the coronavirus and more than half of all Americans had signs of previous infections, Centers for Disease Control and Prevention researchers estimated in a report last month.

The researchers examined blood samples from more than 200,000 Americans and looked for virus-fighting antibodies made from infections, not vaccines. They found that signs of past infection rose dramatically between December and February, when the more contagious omicron variant surged through the U.S.

In the CDC report, the most striking increase was in children. The percentage of those 17 and under with antibodies rose from about 45% in December to about 75% in February.

Currently the U.S. offers a booster dose starting at age 12 but Pfizer and BioNTech  asked the Food and Drug Administration to allow healthy elementary-age kids to also get one -- about six months after their last shot. The companies cited a small study showing the extra shot for kids ages 5 to 11 revved up antibodies capable of fighting the super-contagious omicron variant. Pfizer’s kid-size shots are a third of the dose given to anyone 12 or older.

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education. The AP is solely responsible for all content.